Nitrogen CycleNitrogen Cycle

What is Nitrogen ?

• nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas

•  nitrogen compounds are versatile organics• All life requires nitrogen-compounds, e.g., proteins and

nucleic acids.• Air, which is 78% nitrogen gas , is the major reservoir of

nitrogen.• Plants must secure their nitrogen in "fixed" form• Animals secure their nitrogen (and all other) compounds

from plants (or animals that have fed on plants).• one of the primary nutrients critical for the survival of all

living organisms.

What is nitrogen cycle?

• is the process by which nitrogen is converted between its various chemical forms.

Four processes participate in the cycling of nitrogen through the biosphere: Nitrogen Fixation Decay Nitrification Denitrification

Nitrogen Fixation

• nitrogen must be processed, or "fixed", to be used by plants. 

• plants and animals are not able to use nitrogen gas in that form. For nitrogen to be available to make proteins, DNA, and other biologically important compounds, it must first be converted into a different chemical form.

 

HOW ?

Ammonification/ Decay

• convert the organic nitrogen within the remains back into ammonium

Nitrification• Ammonia by decay converts it to Nitrates• It is important for the ammonia to be

converted to nitrates because accumulated nitrites are toxic to plant life.

Dennitrification

• Denitrification reduces nitrates to nitrogen gas, thus replenishing the atmosphere

Importance of Nitrogen Cycle

• Nitrogen is one of the primary nutrients critical for the survival of all living organisms. Although nitrogen is very abundant in the atmosphere, it is largely inaccessible in this form to most organisms

• Nitrogen is arguably the most important nutrient in regulating primary productivity and species diversity in both aquatic and terrestrial ecosystems

• Clearly illustrates the key role played by microorganism in a well-balance ecosystem.